SPARK PLUGS!!!! ARE THEY A HYPE OR ARE THEY FOR REAL?

[SPEEDY88]

A mecahnic told me that the bosch+4 are all hype and not what they promise....I have them on my car and he advised me to change the plugs and install motorcraft spark plugs. What do you guys think???? should I do it or not?

[TEXSN95]

YUP

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Clint L.
White 95 Cobra #3637
58cc GT40X heads with mild porting, Crane 2031 cam, FRPP 65 TB, 1.7s, Cobra intake, homeade cold air, 155lph, pullies, Tokico Illuminas, C springs, GW LCAs, Kenny Brown super subs, Steeda CC plates, aluminum driveshaft, Steeda quadrant, B&M ripper, Kirban FPR, MSD6A, Taylor wires, Mac shorties, off road hpipe, 2 1/2 ultra flows w/ dumps, R hood, Euro clear corners, stock 3.08s
13.61 @ 105.7 w/ 2.22

[jimberg]

I agree with your mechanic. Go with copper core Autolite 24s. Hyped plugs like Bosch+4s or SplitFire try to give you the impression that electricity will arc to all electrods at the same time. It doesn't work like that. You'll get one arc just like you would with regular plugs.

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351W 89 Mustang GT Convertible

[Gonzo GT]

It's hard to beat a set of side gapped Autolites.

[dinomite]

yup, basic autolites are just fine, platinum, splitfire and the 4 tippers do nothing.

This is what i've learned about spark plugs:
Copper is most conductive
Platinum lasts longer, but is less conductive
The thing that gives you more power is having a higher output ignition system with larger gaps. Having the spark travel farther is the only way to get faster ignition, the spark chooses the shortest ground and as a result only 1 of the prongs in those 4 prong spark plugs even gets used. The reason you want a better ignition system with the larger gaps is so that there's enough applied voltage to overcome the resistance posed by the gap and also because increasing the gap (thus increasing resistance) has a tendancy to stress most stock ignition systems. Don't waste your money, regular scheduled plug changes with the recommended plugs are the best and cheapest way to go and it keeps your car running it's best. A full multiple spark after market ignition is the best way to get power from you ignition system as well as all the matching components/wires/plug gaps/plugs is the best way to go for more power through the ignition system. Good luck, hope this helped.

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'84 Mustang 5.0 LX
My car

[Unit 5302]

Hmmm.. I thought platinum created a weaker spark, not that it was less conductive.

Platinum does have one thing going for it though, it's a catalyst which helps burning.

Regardless, platinum is more likely to miss than copper, and that means performance loss.

[jimberg]

I hate to disagree with you Unit, but platinum is much less likely to miss, that's why they use it. The benefit of platinum plugs is that they last much longer and spark much more reliably at lower voltages. The problem is that since the voltage is much lower, the spark is much colder.

We performance oriented type people change our plugs often enough that we could care less if our plugs last for 100k miles, but we also want a nice hot spark to go with our high performance coils. Copper core plugs give us that.



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351W 89 Mustang GT Convertible

['86FOX-5.0]

Question for 84stanglx. Lets say that you have an aftermarket ignition system (crane Hi-6 w/coil). Will the supposedly "higher end" spark plugs make a difference then, or does it still not matter?

[Mach 1]

Since you shelled out the cash and got ripped off already, you might as well keep the bosch rip-off plugs in there(if your motor is mostly stock) and chalk it up to a lesson learned and buy the cheap plugs next time.

some thoughts on other comments-

platinum does conduct more poorly than copper, thus the weaker spark.

This would lead one to believe that it is not more reliable at lower voltage.

And to the best of my knowledge, platinum retains heat more than copper, which keeps combustion chamber temps. higher (can be bad for performance generally speaking, depending on your application)

Platinum is used for long life only, right? Maybe less likely to miss after 100,000 miles, but when new, not a concern.

these platinum plugs are all part of the new car 100,000 tune up schedule, are great for hard to reach installs, but generally worse for performnace.

[jimberg]

Mach 1,

Although platinum does conduct more poorly than copper, that's not the reason why it has a weaker spark. The only time you're conducting through platinum is at the very tip of the plug. The tip is only coated with platinum, BTW. Platinum acts as a catalyst to allow a spark to occur at a lower voltage than your typical steel tipped plugs. They fire much more reliably because of this, especially with the wimpy coils that they put in cars these days. Since the platinum is also more durable, it holds the gap much longer. Current fuel economy and emissions requirements are what is driving their use, not just there durability.

I suppose we're all familiar with the plumbing analogies related to voltage and amperage. Amps measure the volume of electricity moving through the wire, and volts measures the pressure of electricity moving through the wire. Think of the tip of the spark plug as a pressure relief valve. A platinum tipped spark plug will pop at a lower pressure than a steel tipped plug. It will also pop with more reliability.

It's probably bad to say "use copper core plugs". It should be more correct to say "use copper core, steel tipped plugs".

The fact that we all can agree on is that platinum plugs have a weaker spark which is not what we want in a high horsepower engine with a high performance coil.

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351W 89 Mustang GT Convertible

[Unit 5302]

LOL, sorry guys.

I give up, I've heard everything under the sun about platinum plugs.

Regardless, seems as though the general concensus is they are worse for performance.

Unit, stick w/ FMS or Autolites. Don't believe the hype !

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'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)

86fox-
If you have an aftermarket ignition, you're still not gaining anything by having the quad tipped plugs, just using good quality plugs that have good ceramic insulation (so it doesn't arc through and ground directly to the block). I personally hate Bosch spark plugs, i've had them in three cars and in every car there were misfires because some of the plugs would have arcs through the ceramic (yes, through that porcelain insulation part) and some of the tips would transfer an excessive amount of metal from the tip and increase in gap by itself over time very quickly because the tip is very skinny. I've never had any problems with autolites and i personally now always buy Motorcraft plugs if i can.
I suppose the best answer i can give you is that most aftermarket ignition manufacturers make their own low resistance, durable plugs designed to handle the higher amounts of amperage [jimberg, i've studied electrical theory (Have ASE certification in electrical auto systems) and learned through the "plumbing analogies" as well ]

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'84 Mustang 5.0 LX
My car

[Mach 1]

Jimberg,

You make some good points, we tend to forget it is only the tip we are talking about anyway, so why isnt there a platinum tip plug with a copper core? Or is there?

Ill stand by my above comments, and dont know enough or care to know any more about platinum to agree or disagree with you, although you never did say why platinum tip plugs have a weaker spark? Firing at a lower voltage shouldnt be a problem or a concern with todays high powered factory ignition systems.

And how can you say todays cars use wimpy coils? Todays cars use excellent coils, and have very reliable and efficient ignition systems. This is one reason why you will see no horespower or fuel mileage gains from a MSD ignition box and/or coil upgrade over stock.

The reason the factory coils are so good, is because they have to be, all part of the effecient system for complete combustion to reduce emissions and increase fuel economy.

[This message has been edited by Mach 1 (edited 07-16-2001).]

[This message has been edited by Mach 1 (edited 07-16-2001).]

[jimberg]

so why isnt there a platinum tip plug with a copper core? Or is there?

I went to the Autolite and NGK website to find out more on how these plugs are constructed and they don't seem to want to say. However, I had an Autolite 25 Platinum plug in the garage that I busted open and cut into the electrode. Look at what I found...



A copper core.

you never did say why platinum tip plugs have a weaker spark?

I thought I did when I wrote:

Platinum acts as a catalyst to allow a spark to occur at a lower voltage than your typical steel tipped plugs

A lower voltage spark means a weaker spark. I should also correct myself at this point and say that not all copper core plugs are steel tipped. Autolite uses chromium-nickel and platinum.

The ads for the new iridium tipped plugs seems to imply that since the iridium or platinum tip is more durable, it can also be much smaller. The size of the tip is probably what allows the spark to occur at a lower voltage. Our non-platinum plugs have pretty much a flat surface for an electrode tip. Won't it be fun when we start debating the pros and cons of iridium tipped spark plugs?

And how can you say todays cars use wimpy coils?

You're correct. I should have said that cars designed around platinum plugs have wimpy coils. This is why if your car comes with platinum plugs you should stick with them. Our Mustangs have excellent stock coils and ignition systems.

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351W 89 Mustang GT Convertible

[This message has been edited by jimberg (edited 07-16-2001).]

[Mach 1]

But the sparks not going to occur at a lower voltage, because you wont have a lower voltage.

This is why I questioned that comment.

Are you saying that cars that come from the factory with platinum plugs have weaker ignition systems designed around the plugs?

If you are, I disagree.



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1993 GT/AOD
'93 Mustang GT

[jimberg]

But the sparks not going to occur at a lower voltage, because you wont have a lower voltage.

You're making the assumption that electricity reaching the plug is instantaneous. It's not. As soon as enough electrons build up on the electrode and are able to make the spark, it will. With platinum plugs it will do this with fewer electrons and thus a weaker spark. Remember the relief valve analogy?

Are you saying that cars that come from the factory with platinum plugs have weaker ignition systems designed around the plugs?

If you are, I disagree.

I'd say they have excellent ignition systems but coils that put out less voltage. If you can show me otherwise, I'm more than willing to accept that.

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351W 89 Mustang GT Convertible

[Unit 5302]

Well, I have the copper cores in my car because regardless of any technicallity, I don't see spending $6 per plug when I'd like to keep my plugs replaced, rather than buying helicoils for plug changes every 100k.



Oh I suppose I should throw my 2 cents into the physics here. If the platinum plug makes a weaker spark, why would it be less likely to miss? If you are running a 5.0 with a good ignition, you don't have to worry about the lower voltage, and say running 10.5:1 compression would be much more likely to cause a misfire with a weak spark. Now of course, you could assume that it will not spark until there is enough voltage to arc period, which would mean it would just take a split second longer than normal to spark as the power builds.

Anyway, the concensus is still platinum plugs for the cars that weren't meant to run them stock are crappy, lol.

[jimberg]

I don't think I ever gave the impression that I think platinum plugs are worth buying or anything. I wholeheartedly agree that non-platinum plugs are better for our purposes.

As for the reason behind a lower voltage spark being more reliable, I wouldn't say that it's more reliable because it is a lower voltage, but because it occurs at a lower volage. If the coil was producing an inconsistant voltage, reducing the level of voltage necessary to cause a spark would improve the likelihood that a spark would occur.

The reliability of platinum plugs also have a lot to do with the material not being destroyed over time. Since the gap stays consistent over a longer period of time, it is less likely to misfire because of improper gap.

Autolite now has titanium coated double-platinum tipped spark plugs which are non-corrosive. Now you don't have to worry about using Heli-Coils.

I should mention that it is possible to get a higher voltage spark with platinum plugs. All you have to do is increase the gap.

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351W 89 Mustang GT Convertible